下面这个4阶行列式用定义怎么求?
问题描述:
下面这个4阶行列式用定义怎么求?
1 0 0 2
0 5 7 0
0 5 6 0
4 0 0 3
答
给你个更一般的
a1 0 0 b1
0 a2 b2 0
0 b3 a3 0
b4 0 0 a4
用定义计算
D = (-1)^t(1234)a1a2a3a4
+ (-1)^t(1324)a1b2b3a4
+ (-1)^t(4321)b1b2b3b4
+ (-1)^t(4231)b1a2a3b4
= a1a2a3a4-a1b2b3a4+b1b2b3b4-b1a2a3b4
= (a1a4-b1b4)(a2a3-b2b3)